Share this page Print

Backyard composting guides and troubleshooting

Typical Calgary yard waste such as grass clippings, leaves, weeds before they seed, tree fruit and berries and the remains of disease-free garden plants make excellent compost.

You can also compost kitchen scraps such as fruit and vegetable peels and trimmings, eggshells, teabags, coffee grounds and filters. Woody yard waste like branches and brush can be used as well in limited amounts as long as they are cut into smaller pieces.

Do NOT compost meat, bones, grease, fat or fatty foods like cheese, salad dressing or leftover cooking oil, as they may attract pests. These items are best suited for the green cart.

What you are allowed to put in a backyard composter and where you can place the composter are covered under our Composting Bylaws.

Here are five common questions we receive about backyard composting:

What can I compost?


DO not compost

Grass clippings and weeds Meat, bones or fish scraps*
Leaves and garden waste

Grease, fats and oils*

Tree fruit, berries and evergreen needles Dairy products*
Branches, hedge clippings, bark chips, (smaller pieces) Cooked and prepared foods*
Dryer/vacuum lint Baked goods, rice or grains*
Topsoil and sod Pet waste* or animal parts and remains
Fruit and vegetable waste Charcoal or coal ashes*
Teabags, coffee grounds, coffee filters and paper towels Clay, gravel or rocks
Eggshells Materials treated with insecticides, herbicides or other chemicals*

* These items are accepted in the Green Cart program.

How do I compost?

Composting requires five basic things

  • Organic material
  • Moisture
  • Air
  • Soil microbes
  • Time

Organic material is divided in to "Greens" (nitrogen rich) and "Browns" (carbon rich). Green materials are usually moist like your fruit and veggie scraps, fresh grass clippings or fresh fallen leaves. Brown materials are dried like dry brown leaves or dry grass clippings.

Follow these basic steps for more effective composting:

Step 1
Choose an area with good drainage and some sun to set up or build your own composter. Depending on your lifestyle and needs, you may choose to use a store-bought or home-made composter. Ideally, your compost area should be at least one metre by one metre by one metre. You do need a fairly large pile for the composting process to begin. If your pile is too small, it will not compost properly.

Step 2
When you begin, you may choose to layer some branches or twigs about one foot long or larger on the bottom of your compost pile to allow for air flow and drainage. A thin layer of soil can be added first to provide the soil microbes that will do the work of breaking down your organic material. There is no need to use compost starter, which basically does the same thing by adding soil microbes.

Then begin to add your materials as you have them. The smaller the pieces you put into your compost heap, the faster they will decompose. You will need to add one-part greens for every part of browns to build a balanced compost heap. It is recommended by some that you layer your greens and browns. However, as long as the ratio is one-part green materials to one-part brown materials, it is not necessary to layer the material as you will be turning the pile mixing these two types of materials anyhow.

Fine materials such as grass clippings should be added in smaller amounts so that they do not compact. Compaction means that there won't be adequate air supply. You can also try "grasscycling." For more information, visit grasscycling.

Step 3
Add water. Effective composting requires moisture. Add water when you first start your compost pile and each time you turn your pile. The compost pile should be as moist as a wrung out sponge to be composting effectively.

Step 4
Turn your pile with a compost aerating tool, pitchfork or shovel every couple of weeks during the growing season to provide an adequate air supply.

If your compost pile has a foul odour, it is likely you need to turn the pile more often to circulate more air, reduce watering or reduce the amount of greens in your pile.

You will know that your compost pile is working when the material starts to heat up. The pile can get so hot at its centre that you couldn't stand to put your hand there.

In the winter, your compost pile may freeze solidly. Just keep adding your green and brown material as usual. In the spring, when it thaws, the pile will pick up the composting process just where it left off the previous winter. Only really large compost piles are insulated enough to continue composting year-round.

Step 5
Your composted material is ready to use when it has an "earthy" smell, is dark in colour, cold and most of the materials are unrecognizable. The composting process can take from two months to two years, depending on the materials used and the effort involved.

How do I use compost?

It is very important to know how to use compost for the health of your gardens and lawns. Compost is not a soil. It is a soil amendment that will add organic matter, microbes and nutrients to your soil. Typically the ratio for use is one-part compost to three-parts soil.

Uses for compost around the home include flowerbeds, vegetable gardens, adding with soil on newly seeded lawns, as a mulch around plants and on established lawns.

Lawn topdressing
For best results, aerate the entire area before topdressing using a commercially available aerator. For topdressing, spread 0.5 to 1.25 centimetres (1/8" to 1/2") of mature compost evenly over the area using a rake. Water thoroughly. The water helps the compost move through the thatch layer to the soil surface and into aeration holes where it can help retain valuable moisture.

Flower beds
For existing beds, add about 2.5 centimetres (1") of compost and work it into the soil using a rake, hoe, shovel or rototiller. Water until the entire root zone is saturated. For best results with new beds, add 2.5 to 5 centimetres (1" - 2") of compost and rototill to at least a 12 centimetres (5") depth. Plant and water accordingly. Most annuals and perennials perform well in compost-amended soils.

Tree planting
Rototill an area about three to five times the diameter of the rootball of the tree to be planted. Add about 30 per cent compost by volume to the area and mix thoroughly outside the hole with the native soil. Place the tree into the hole and use the compost amended soil mixture as a backfill around the rootball. Remove excess soil and water thoroughly.

Vegetable gardens
Apply about 2.5 centimetres (1") of compost and incorporate into the soil to a depth of 12 centimetres (5") with a rototiller or by hand. For poor soils, you may need to apply compost on a yearly basis until the soil has improved to your satisfaction. Do not over apply compost because many vegetables will not produce high yields if excess nitrogen is in the soil. Compost used as a mulch can be turned into the soil prior to replanting.

For mulch applications around annuals, perennials and other landscape plants, a 5 centimetres (2") layer of compost is optimum. Apply compost and rake to achieve an even application. Avoid over or under mulching because other problems can arise, such as smothering of root systems. Arrange mulch so water flows away from trunks, reducing chances for crown rot. Finer-textured composts do not suppress weeds as well as coarse-textured composts.

Lawn establishment
For lawns that are going to be seeded or sodded, apply about 2.5 to 5 centimetres (1" - 2") of compost and rototill to a depth of 12 centimetres (5"). For seeded lawns, apply seed and then a slight dusting of compost to cover seed. For sod and seeded lawns, thorough irrigation is necessary. Compost helps increase grass seed germination by providing adequate seed to soil contact, moisture and balanced nutrients. A regular fertility program should be established once the lawn is about eight weeks old or when it has been mowed for the second time.

Compost tea
Compost tea is a good "perk" for your plants. It's simple to make and easy to use. Fill a cloth bag with compost and put it in a barrel or bucket of water. Your mixture should be about one-part compost to five-parts water. Let it steep for about a week, swirling it around a few times and make sure that the "tea bag" is submerged. You can then pour the "tea" over your plants. Put the compost bag either back into your composter or spread it in the garden.

What are the signs that I'm not composting properly?

Composting is not difficult but sometimes the process requires a little extra attention. Here are some easy solutions to correct certain situations that might occur.

The composting process takes too long
If the pile does not decrease in size or generate heat, composting may need a boost. If the pile is dry, add water and mix thoroughly. If the pile is wet and muddy, spread it in the sun and add dry material. As well, the items in the pile may be too large. Chop them into smaller pieces. Remember to save "old" compost to mix with incoming material.

The centre of the compost pile is damp, but the rest dry
The compost pile may be too small. Try to keep your composter as full as possible. Mix new with old, dry with wet, breaking up mats and clumps.

The compost pile is damp and sweet smelling but not heating
The pile may need more greens (nitrogen). Add grass clippings, fruit or veggie scraps or a sprinkling of organic fertilizer from the garden centre.

The compost pile smells like ammonia
The pile may have too many greens, add more browns (carbon). This will likely happen if you have added too many fresh grass clippings.

The compost pile smells like sulphur (rotten eggs)
The pile may be too wet and not be getting enough air. Loosen up the pile, break up clumps, unblock vents and perhaps add some wood chips to help the pile "breathe". Turning the pile always helps aeration.

The compost pile is attracting pests
Compost in a container with a cover to prevent animals from getting into the composting materials. A wire mesh around the base can help to prevent pests from digging under the pile. Dig in or cover food waste immediately. If done properly, composting should not attract pests.

What kind of backyard composters are there?

Depending on your lifestyle and needs there are many types of composters. Composters can be store-bought or home-made. They all do the job, with Mother Nature's help. There are several common types including the one, two and three compartment, wood bins, plastic bins and many kinds of fenced/wire bins.

It is quite easy and cost effective to build your own bin. They are also sold at many home improvement stores and the Green Calgary EcoStore, located at the corner of 14th Street and 2nd Avenue NW. You can contact the EcoStore by calling 403-230-1443 ext. 222 or visit the EcoStore online.

Types of Composter Bins

Rotating Barrel Bin
A rotating composting bin is effective for those wanting to compost in batches. It can ease the aerating and turning requirements for obtaining compost. Note that this type of composter is essentially a heavy rotating barrel, safety considerations must be taken as it may be difficult to turn when full.

Three Compartment Bin
The three compartment composting bin is meant for a fast continual feed with the advantage of processing large amounts of material in batches. Material can be mixed between two of the compartments, while the third compartment can be used for curing and storage.

Two Compartment Bin
This system is a smaller version of the three compartment bin. It has the space for turning the composting material, but does not have a third compartment for curing and storage.

Soil Saver Classic
The square shaped plastic Soil Saver Classic comes complete with a toll free composting hotline. It is easy to assemble, and tends to be preferable in an urban setting.

Wire Bin
The wire bin is a cost effective alternative to composting in batches. It folds out for easy assembly. Note that due to the dry climate in Calgary, this composting bin will require substantially more watering.

How does backyard composting work with my green cart?

The green cart can be used alongside your backyard composter because it accepts more material than can be composted at home like meat, bones, dairy, pet waste and weeds.

When your backyard composter is full you can put additional food or yard waste into the green cart or in paper yard waste bags for weekly collection.

Can I compost if I don't have a yard?

Another composting alternative is vermicomposting – composting with worms. Red worms or red wigglers are a type of worm that thrive in organic materials and can eat an amount equal to their weight every day. They produce castings that are a rich compost. They can go through three pounds of garbage per week, keeping unnecessary waste out of the landfill and returning much needed nutrients to the soil.

Visit the Green Calgary website for more information on how to start vermicomposting.

Where else can I find more information?

Green Calgary has an informative website with information about composting and other ways to reduce, reuse and recycle or they can answer your composting questions at 403-230-1443. Green Calgary also offers composting workshops (for a small fee), contact them at 403-230-1443 for times and availability.